(1) Field of the Invention
The present invention relates to an intelligent safety alert system which recognizes when a swimmer is in trouble and transmits an alarm or warning signal to a parent, companion, and/or monitor.
(2) Prior Art
Water safety devices are known in the prior art. U.S. Pat. No. 4,932,009 to Lynch illustrates one such device and a method for detecting the presence of submerged, possibly distressed swimmers. The Lynch device employs a plurality of pairs of transducers arranged on opposite sides of a body of water. Pulsed sequential excitation of the transducers is employed to monitor the body of water. A person disposed between a pair of transducers interrupts the transmission of ultrasonic waves. An alarm is triggered upon the interruption of the ultrasonic waves or after a delay to avoid false alarms, warning of the presence and location of a submerged, lingering swimmer even in the presence of other active swimmers in the body of water. One of the problems with this type of device however is that it can not be easily used in open bodies of water.
U.S. Pat. No. 5,097,254 to Merrithew illustrates a device worn by a swimmer. The device includes a portable sonic signal generating member having a switch or similar device which is activated at a predetermined depth. The device also includes a timer for detecting immersion at the predetermined depth for the predetermined time. On immersion occurring at the predetermined depth for the predetermined time, a sonic signal is generated, and detected by a receiver mounted in the pool. An alarm signal is generated to operate an alarm device. Again, the device is not one which could be used in open bodies of water.
U.S. Pat. No. 5,408,222 to Yaffe et al. illustrates another device, worn by a swimmer, for issuing a warning when a person is submerged beneath water. The device comprises a timing circuit having first and second terminals. The timing circuit is responsive to a voltage applied to the first terminal for connecting the second terminal to the first terminal after a predetermined time interval. An alarm unit is connected to the second terminal of the timing circuit. A normally open water-sensitive switch is attached to a part of the person's body which is normally above water and is coupled to the first terminal of the timing circuit. An electrical supply is coupled to the water-sensitive switch for applying the required voltage to the first terminal of the timing circuit when the water-sensitive switch is submerged beneath water. A normally deflated float may be worn by the person so as to be automatically inflated in response to the alarm signal.
U.S. Pat. No. 5,268,673 to Nelson et al. illustrates a swimming pool alarm responsive to wave motion that produces a signal when two waves exceeding a threshold level of amplitude are sensed within a preset duration of time. A transducer senses air or water pressure changes and produces electrical signals corresponding to the changes. A comparator system, connected to the transducer, receives the transducer signals and, if the signals exceeds a preset threshold level, transmits a signal to a discriminator. The discriminator times the signals received from the comparator and when two signals are received within a specified period of time, a third signal is generated. A warning device such as an alarm is connected to the discriminator and is activated by the third signal.
None of these devices has the capability to recognize the characteristics that indicate when a swimmer is in trouble. These devices produce an underwater signal and a subsequent alarm when a pressure threshold is exceeded or when a period of time has elapsed. In these cases, the swimmer may or may not have a problem. The potential for frequent false alarms exists.
Despite the existence of these devices, most frequently lifesaving personnel and concerned parents depend on visual recognition of a potential problem when children are playing in water. This means of detection is subject to human error and sometimes results in tragedy. The element of distraction and the inability to track a child in a crowded environment increase the risk of a problem.